This section provides background information related to the present disclosure which is not necessarily prior art.
In automotive vehicles, it is common to have a climate control system located within an instrument panel which provides heated or cooled air to occupants through dash panel defrost air outlets, instrument panel venting air outlets and floor directed air outlets. These traditional climate control systems often include a heater core that performs heat exchange between the engine coolant, which is heated by the engine, and the cool air in the cabin/outside environment, in order to provide warm air to the passenger compartment. Some vehicles include an air conditioning system that incorporates an evaporator for absorbing heat from the warm air in the cabin and from the outside environment. The heater core and evaporator are typically provided in an HVAC housing located in the passenger compartment of the vehicle. The evaporator and heater core are generally disposed downstream of a fan for communicating cooled or warmed air into the passenger compartment.
Distribution or control or blend air doors within an HVAC unit are used to control the various airflows through the heat exchangers. When a “full hot” condition is required, the air doors shut off airflow from non-heated air sources. Conversely, when a “full cold” condition is required, the air doors shut off airflow from the heated air source. In “medium mode” conditions, when temperature other than “full hot” or “full cold” is required, the air doors may be positioned to allow heated and non-heated air streams, in varying degrees, to pass through the HVAC unit.
The air output from the HVAC unit may be supplied directly to various outlets within the vehicle cabin. It is desirable to be able to provide air through the outlets simultaneously which are all at substantially similar temperatures
A heater core typically does not produce uniform temperature distribution across its plane. As a result, a temperature gradient is observed along the heater core. With a typical HVAC configuration, sometimes an undesirable temperature imbalance is observed between the center and outside panel vents in the cabin of the vehicle, known in the art as stratification. Conventional methods to compensate for the temperature imbalance are to increase tank depth of the heater core, increase thickness of the heater core, or shift the position of the heater core inside the case. All of these options involve costly tooling changes and can have a negative impact in terms of airflow volume and noise.